We playtested it yesterday and the wizard's Ray of Frost was extremely powerful. The party encountered the Owlbear and the wizard saved the day by freezing it (with a roll of 7+) almost every round. The others stood away from the owlbear and attacked with ranged attacks, slowly grinding down it's 110 hit points. Twice the wizard failed his ranged attack and the owlbear did a little damage. If the players had stood away more than 30 feet from him, he wouldn't even have managed to do that, since he couldn't have reached them in one round. All in all, the fight felt very boring. I hope they'll change Ray of Frost.